The resistance needed will change depending on the voltage supplied. If you have a 4v DC
transformer, you shouldn't need any resistors to run a single led
. For multiple leds wired in series, you'll need more voltage to run the string, wired in parallel the voltage will be fine as long as your transformer can support the current. Led
's are very low draw, so it shouldn't be an issue to run several with just about any transformer you can find.
And Yak is right. You're much better off experimenting with low voltage/current DC
than high voltage/current AC
. To be real safe, play with 3 AA batteries and an LED
: ) That would give you 4.5v dc
and run an led
for quite a while.